Analog Devices Inc./Maxim Integrated MAX6423XS23+T

Overview

MAX6423XS23+T from Analog Devices is a low-power microprocessor supervisor IC with open-drain active-low reset output, 2.313V ±2.5% factory-trimmed reset threshold, capacitor-adjustable reset timeout (275µs to 5.75ms), and guaranteed operation down to VCC = 1V. It monitors supply voltage in portable and battery-powered systems to prevent erroneous µP execution during power-up, brownout, or power-down events.

For engineers reviewing the MAX6423XS23+T datasheet, MAX6423XS23+T pinout, MAX6423XS23+T application, or MAX6423XS23+T equivalent, key selection criteria include its SC70-4 package, 1.6µA typical quiescent current, open-drain RESET compatibility with multiple logic supplies, immunity to short VCC transients, and precise 240nA SRT ramp current for accurate timeout setting.

Technical Context

The MAX6423XS23+T implements a precision voltage detector with laser-trimmed internal resistors defining a 2.313V nominal reset threshold, with ±2.5% accuracy over –40°C to +125°C. Its reset assertion is triggered when VCC falls below this threshold, and deassertion occurs after an externally set timeout period determined by the SRT pin's 240nA constant-current source charging a capacitor to 0.65V.

As an open-drain device, it requires an external pullup resistor (10kΩ–100kΩ) to any supply up to 5.5V, enabling flexible logic-level interfacing and wired-OR reset capability. The SRT pin is highly sensitive to stray capacitance and leakage, demanding careful PCB layout to maintain timeout accuracy.

Key Specifications

Pinout & Package

MAX6423XS23+T is housed in a 4-pin SC70-4 package (package code X4+1, outline 21-0098), measuring 2.0mm × 2.1mm × 0.95mm, with gull-wing leads and RoHS-compliant lead-free finish ("+T" suffix).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar microprocessor reset supervision applications.

Compared with MAX6423XS23+T, MAX6423US23+T offers identical supervision functionality in a different package, while NCP302LSN23T1G trades adjustability and interface flexibility for lower unit cost and simpler BOM-but mandates layout changes and forfeits timeout tuning.

Availability

MAX6423XS23+T is available at Aetrix Electronics and suitable for portable equipment, battery-powered controllers, and automotive body electronics requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MAX6423XS23+T includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Analog Devices is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.

The MAX6340/MAX6421–MAX6426 family was designed specifically for ultra-low-power, precision voltage monitoring in space-constrained portable and battery-operated systems where reliability under brownout and transient conditions is critical.

FAQ

What is the exact reset threshold voltage of the MAX6423XS23+T?

The MAX6423XS23+T features a factory-laser-trimmed reset threshold of 2.313V, with ±2.5% accuracy over the full –40°C to +125°C operating temperature range. This value is confirmed in Table 1 of the datasheet and corresponds to the "23" suffix in the part number. The MAX6423XS23+T does not require external calibration and maintains this threshold stability across voltage and temperature variations.

How do I calculate the reset timeout capacitor for the MAX6423XS23+T?

For the MAX6423XS23+T, use the formula CSRT = (tRP − 275µs) / 2.735 × 10⁶, where tRP is the desired timeout in seconds and CSRT is in farads. For example, a 4.375ms timeout requires a 1500pF capacitor. The SRT pin sources a precise 240nA current, so ceramic capacitors with <10nA leakage are mandatory for accuracy-avoid electrolytic or high-leakage dielectrics.

Can the MAX6423XS23+T drive a 5V µP reset input directly?

Yes-the MAX6423XS23+T's open-drain RESET output can interface directly with a 5V µP reset input using a pullup resistor to 5V. Its RESET pin is rated for up to 6.0V, and leakage is limited to 1.0µA when deasserted. A 10kΩ pullup ensures robust logic-high levels while keeping sink current within spec when asserted, making the MAX6423XS23+T ideal for mixed-voltage systems.

Is the MAX6423XS23+T qualified for automotive applications?

While the MAX6423XS23+T itself is not individually AEC-Q100 certified, it belongs to the MAX6340/MAX6421–MAX6426 family, within which the MAX6340UK31/V+T variant is explicitly AEC-Q100 qualified. The MAX6423XS23+T shares identical BiCMOS process, design, and testing methodology, and operates across –40°C to +125°C-meeting core automotive ambient requirements. System-level qualification remains the responsibility of the end designer.

Why does the MAX6423XS23+T specify VCC down to 1.0V but guarantee RESET validity only to 1V?

The MAX6423XS23+T functions and asserts RESET down to VCC = 1.0V, but its RESET output voltage levels (VOL/VOH) and sink/source capability degrade below 1.0V. The "guaranteed RESET valid to VCC = 1V" specification means that for VCC ≥ 1.0V, the output meets all logic thresholds and current-drive specs-ensuring interoperability with µP reset inputs. Below 1V, behavior is unspecified, so system design must ensure VCC stays ≥1.0V during RESET assertion.